The inventive concepts described herein relate semiconductor devices, and more particularly, to data storage devices.
Semiconductor memory devices can include volatile semiconductor memory devices and nonvolatile semiconductor memory devices. A read speed and a write speed of the volatile semiconductor memory device may be relatively fast, but when a power supply is interrupted, data stored in a volatile semiconductor memory device is not retained. On the other hand, even though a power supply is interrupted, data stored in a nonvolatile semiconductor memory device is retained. Therefore, the contents stored in nonvolatile semiconductor memory devices can be preserved regardless of whether power is supplied.
Examples of data storage devices using nonvolatile memory devices include a solid state drive (SSD), an embedded Multi Media Card (eMMC), and the like. General data storage devices may be manufactured in finished form and shipped by a memory vendor after firmware is programmed.
However, a memory vendor may produce a controller, a nonvolatile memory, and the like and may deliver the products to a fabricator. The fabricator may mount a controller, a nonvolatile memory, and the like on on-board type data storage. The on-board type data storage may be delivered with firmware programmed.
However, since nonvolatile memory may be mounted on a board by surface mounting technology (SMT) at a relatively high temperature in the on-board type data storage, a threshold voltage distribution of memory cells may be changed. This may cause an uncorrectable error or a boot fail.